Cold flow preventing packing structures



y 5 v I .J. 'R. BAKER 2,896,724

COLD FLOW PREVENTING PACKING STRUCTURES Filed Aug. 26, 1957 INVENTOR.clam/1?. finmse BY I Y Arraewzm Unilifid tates Patent COLD FLowPREVENTING PACKING,

STRUCTURES,

John. R. Baker, Pasadena, Calif., assignor tov Baker Oil 'flools, Inc.,Los Angeles, Calif., a corporation of Caliornla A ca on u t a 2 .7 Seial, a. 6. .0.10; Claims. (0!. 1661-204) The present. invention relatesto subsurface well tools, and more particularly to packing devicesadapted to be disposed i n'well bores foreifecting sealsagainst casings,liners, and the like, previously located. within the well bores. i

Packing elements employed in well boresare ordinarily made of rubber orrubber-like materials, or. similar pliant, elastic materials. Thepacking element usually bears against an abutment having a'substantialclearance with the wall of the surrounding well casing,liner, or the like. Upon being subjected to substantial forces, thepacking element tends to cold flow into the clearance space aroundtheadjacent abutment. Such coldflowing action ismost pronounced inwellbores having relatively high temperatures and pressures. In someinstances, the cold flowing is of such an extent as to result in theforcing of a large portion, if not all, of the packing material, intothe clearance space, resulting in failure of. the packing element. i

'It is an object of the present invention to provide an improved packingstructure embodying a pliant, elastic packing element whichisprevented-from cold flowing into the clearance space around an adjacentabutment, despite the fact that the packing element might be subjectedto high pressures, high temperatures, or both Another object oftheinverition is to provide a packing structure, which includes apliant, elastic packing element and a coldflow preventing device forprecluding shifting of the packing material around an adjacent abutment,the packing element being instrumental: in shifting the coldfiowpreventing devic eto its operative position, there being no spaces inthe preventing device through which he packing material can be forced.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparentffrom a consideration ofa forniin which it may be embodied. This form is shown in" the drawingsaccompanying and forming'part-of the present specification. It will nowbe described in detail, for the purpose of illustrating the generalprinciples of the invention; but it is to be understood that suchdetailed description is not to be taken in a limiting sense, since thescope of the invention is best defined'by the appended claims.

Referring to the drawings:

Figure 1 is acombined longitudinal section and side elevational view ofthe well packer disposed in a Well casing, with the packer parts'intheir initial, retracted positions; c v

Fig. 2 is a view similar to Fig. 1, illustrating the Well packer afterit has been anchored in packed-off conditionin the well casing; i

Fig. 3 is a plan view of the flow preventing device, with parts brokenaway;

Fig. 4 is an enlarged fragmentary longitudinal section through the flowpreventing device. a

The, packing. structure 10. is illustrated by way of example in thedrawings as forming part of a Well packer A to be anchored inpacked-ott.condition within a well 2,896,724 Patented July 28, 1959 casing B, orthe like. The well. packer itself is adapted to be lowered in the wellcasing to. the desired setting point by means ofa tubular string C, suchas a string of tubing, with the exterior parts of the wellpackerdisposed initially in a retracted'position to permit freedom of passagethrough the casing to the desiredsetting point; The packer includes amain body 11 which carries a set of upper segmental slips 12 adapted tobe moved into engagement with the casing B by an upper frustoconicalexpander 13 retained initially in retracted position by one or moreshear screws 14 securing it to the main body. The .upper slips are alsoretained initially in retracted and inelfective position by shear screws15, 16 securing them to the expander and the main body. A lower set ofsegmental slips 17 is initially held in retracted position, by beingattached to the main body 11 through the medium of shear screws 18 andto a lower frusto-conical expander 19 through additional shear screws20, this latter expander being held initially in inefiective position bysuitable frangible connections in the form of shear screws 21 threadedinto the body 11. The packing structure 10 includes a packing sleeve 22of synthetic or natural rubber positioned between the expander's 13, 19,being retained initially free from contact "with the casing 'jwan, butbeing capable of foreshortening and expansion into engagement therewithand the main body 11 of thepacker. a

A valv e assembly housing 23 is threadedly secured to the lower end ofthe main packer body 11, carrying there. within atripping ball sea t 24initially secur ed thereto by a shear This seat has i an upstanding "armZ Gfor'hoIding a buoyant back pressure ball- 2 7 in ineffective positionagainst the interior of the housing, to preventits: seating against avalve seat 28 provided at the aw reness thefinain body. *Rerrioval of"this arm 26 through a proper operation will permit the" ball '27 to berqsit n da ns t qr b 'e a v '5??? 5 Whimi everreverse flowthroughjthebody 11 tends to occur. Thewell packer A "run in the casing' QB' to thedesired setting point and olIiCllidtitlld established there} i h g ntersany p e fi o e lma s in. th? well casing. Thereafter, a tripping ball islowered or Pa r l wn i sueh t e t n String G. t e t engagement withthetripping ball seat 24, permitting inre se'st' s P ess e 9 b? i wi lhe. fl s s? d'y. '1 an i s ge h ugh, P P-" earni through the'body intothelinteriorof the packing sleeve flu i u s Pre u w l a th srs and h tth ur'r r' expander rwa' d Y l n he body '11 to disrupt the variousshear screws 15, lo and if he rr lip g an u pe et g n se u sdt t e o nsu wl r l nt g ipp n engagement with the well casing B After the uppersl-ips i2" have been set the manner described, the r s r c he fl s is nfas 9; shea h S r w ho d het i p n ba ea t e alvsh usin I 61 u sie i h e.21 wea her W h its piii m. r m the al e o sin a llowin theback pressureball 27 'to engage theseat 2.8 whenever reverse flowof fluid tends tooccur. 7

Anupwardly dir cted pull": train then taken on ar S r n 0 unma od .1 fthe P e fi i j rtntherak a. sl e 22 by. mov n e jl w ex ande 2 wardhbjupper p n e 13 and x ml: he a kin sle ve ainstft e. cas ng w l s L tbo the ma n bdy 1.1 A con u n of h ly e l s st e n. a the ubul trln v c.and ibody B w ill shear the screws-1Q, 2]), 21- holding the lower sips-1 7101% bddyfand expander' 1 9, aiidthe expander 19to the' body1l,'".c ausia'g an abutment "32 at the lower end of the" body a 11 toengag'flief" slips 17 and move them longitudinally along the outer faceof the lower expander 19 and radially into engagement with the casing B.An increase in this upward strain will further move the lower slips 17and expander 19 toward theupper slips 12 and expander 13, furthercompressing the packing sleeve 22 between the casing wall B and exteriorof the body 11,to effect aleakproof seal therebetween.

The parts are retained in the set position illustrated in Fig. 2 .bypreventing downward movement of the body 11 relative to the partsurrounding it. This can be accomplished by providing a split,contractile ratchet ring 33 in an internal groove 34 in the upperexpander 13, this ratchet ring being adapted to engage circumferentialratchet teeth 35 formed in the periphery of the packer body. The teeth35 on the body face in a downward direction whereas the ratchet ringfaces in an upward direction, so as to permit the body 11 to moveupwardly relative to the upper expander 13, but precluding downwardmovement of the body with respect thereto.

The upper and lower expanders 13, 19 form abutments at the upper andlower ends respectively of the pliant, elastic packing element or sleeve22. As disclosed, the end portions 22a of the packing sleeve may bereduced in diameter to fit in companion recesses 40 in the upper andlower abutments or expanders. To assure the passage of the well packer Adown through the fluid in the well casing B, a substantial annularclearance 41 is provided between the abutments or expanders 13, 19 andthe wall of the surrounding well casing. Such annular clearance space isa source through which the rubber or rubber-like packing material 22 canbe extruded, following the setting of the packer and expansion of thepacking sleeve 22 into sealing engagement between the body 11 of thetool and the wall of the well casing B. Such extrusion can occur morereadily when the well packer is subjected to high temperatures or highpressures, and will occur most readily when the packing sleeve issubjected to a combination of high pressures and high temperatures.

The present invention prevents the cold flowing or extrusion of thepacking material through the clearance space 41 existing between anabutment 13 or 19 and the wall of the surrounding well casing B. Toaccomplish this purpose, an extrusion preventing device 42 is providedat each end portion of the packing sleeve 22 and the adjacent abutmentor expander. As specifically disclosed, the end 43 of the upper abutment13 is tapered in an upward and outward direction, the confrontingportion 44 of the packing sleeve 22 also being tapered, but in adownward and outward direction, thereby defining a generallytriangularly-shaped groove 45 between the tapered surfaces 43, 44 whichextends circumferentially around the abutment and the confrontingportion of; the packing sleeve. An outer metallic ring 46 is positionedin the groove 45, having an inner tapered surface 47 engageable andcompanion to the tapered surface 43 on the abutment. This ring is alsoof generally triangular cross-section. In fact, it may be of generallyright triangular cross-section, with its outer surface 48 generallycylindrical, and with its lower surface 49 relatively flat andsubstantially normal to the axis of the well packer.

A-n inner ring 50, reversely arranged to the outer ring 46, is alsodisposed in the lower. portion of the groove 45, having a tapered innersurface 51 engageable with and companion to the tapered surface 44 onthe packing sleeve 22. This inner ring 50is also of generally triangularcross-section. As specifically disclosed, it is of generally righttriangular cross-section, with its outer surface 52 generallycylindrical and forming a continuation of the outer surface 48 of theother ring 46. Its upper surface 53 may also be normal to the axis ofthe well packer and abuts the lower surface 49 of the outer ring Theinner and outer rings 50, 46 substantially fill the triangular groove 45defined by the tapered surfaces 43, 44 on the upper abutment 13 and theconfronting face of the packing sleeve 22. These rings are each splitand normally tend to remain in a retracted position, such as disclosedin Fig. 1. However, the rings 46, 50 are expandible outwardly to bringtheir cylindrical surfaces 48, 52 into engagement with the cylindricalwall of the well casing B. The splits 60, 61 of the rings are staggeredwith respect to each other. In fact, they are preferably arrangedapproximately degrees from. one another.

To assure the same extent of outward expansion of the rings, they arekeyed to one another, for circumferential slidable movement with respectto one another, but with relative radial movement being prevented, by anarcuate key and slot arrangement. As specifically disclosed, one of therings 50 has a circumferential r-ib 62 projecting upwardly from itsupper face 53, this rib fitting within a companion circumferentialgroove 63 in the lower portion of the outer ring 46. By virtue of thekey and keyway or'slot arrangement 62, 63 described, the rings 46, 51will expand outwardly to the same extent, as described hereinbelow.However, the interconnection 62, 63 between the rings will not prevent.such expansion from occurring. By placing the splits 60, 61, 180degrees from one another the rings together exert a uniform force aroundtheir circumference resisting their outward expansion.

. If desired, a similar flow preventing device 42a may be providedbetween the lower expander or lower abutment 19 and the confrontingportion 44a of the packing sleeve 22.

In the operation of each flow preventing device, when the packer body 11is moved in an upward direction, after the upper set of slips 12 hasbeen expanded against the well casing B, in the manner described above,the lower abutment or expander 19 is moved by the body toward the upperabutment or expander 13, foreshortening the packing sleeve 22 andcausingit to shift outwardly against the wall of the well casing. During theforeshdrtening of the packing sleeve between the abutments 13, 19 andits outward expansion, the tapered surface 44 on the packing sleevebears against the tapered surface 51 on the inner ring 50 and urges thelatter in an outward direction toward the wall of the well casing.

The upward force imparted to the packing sleeve 22 is transmittedthrough the inner ring 50 to the outer ring 46, the tapered surface 47of the latter bearing upon the companion tapered surface 43 on the upperexpander or abutment 13, which also effects an outward shifting of theouter ring 46 toward the well casing B. The combination of the taperedsurfaces 44, 43 on the packing sleeve 22 and on the'abutment 13 shiftsthe outer rings 46, 50 outwardly, such rings moving outwardly to thesame extent in view of their arcuate or circumferential key or rib andgroove or slot interconnection 62, 63, until both rings are brought intofirm engagement with the wall of the well casing. When so engaged, theouter ring 46 still has substantial engagement with the abutment 13.Each ring will contact the wall of the well casing for substantially 360degrees, except for the arcuate extent of split 60 or 61 in each ring.However, since the slots or splits 60, 61 are staggered with respect toone another, the inner and outer rings 46, 50 of each flow preventingdevice will engage the wall of the 'well casing B and bridge theclearance space 41 between the abutment :13 and the-well casing, no gapsor spaces existing through the flow preventing device 42 into andthrough which the packing material can flow (Fig. 2).

If the lower flow preventing device 42a is used it will also be expandedoutwardly as a result of the longitudinal forces imposed upon thepacking sleeve 22, the inclined surfaces coacting with one another toeffect a shifting of both rings 46, 50 of the lower device outwardlyuntil their cylindrical surfaces 48, 52 engage the wall of the wellcasing B.

The rings 46, 50 of each extrusion preventing device 42, 42a may be madeof a suitable material which will withstand comparatively high pressuresand temperatures without deforming their cross-section. For example, therings may be made of ductile iron. When made of such material, the ringswill not deform significantly and will always bridge the clearance space41 between each abutment and the wall ofthe well casing, resistingextrusion into the clearance space.

' The inventor claims:

1. A packing structure, including a non-metallic packing member adaptedto engageia companion wall, an abutment adjacent said member and havinga tapered expander surface, a first split functionally integral ringengaging said packing member, a second split functionally integral ringengaging said tapered surface and said first ring and circumferentiallyslidable on said first ring, and means securing said rings to oneanother for joint movement toward engagement with the companion wall inresponse to movement of the packing member into engagement with thecompanion wall.

2. A packing structure, including a non-metallic packing member adaptedto engage a, companion wall and having a first tapered expander surface,an abutment adjacent said member and having a second tapered expandersurface opposite said first expander surface, a first split ringengaging said first tapered surface, a second split'ring engaging saidsecond tapered surface and said first ring and circumferentiallyslidable on said first ring, and means securing said rings to oneanother for joint movement toward engagement with the companion wall inresponse to movement of the packing member into engagement with thecompanion wall.

3. A packing structure, including a non-metallic packing member adaptedto engage a companion wall and having a first tapered expander surface,an abutment adjacent said member, a first split ring engaging saidtapered expander surface, a second split ring engaging said abutment andsaid first ring and circumferentially slidable on said first ring, andmeans securing said rings to one another for joint movement towardengagement with the companion wall in response to movement of thepacking member into engagement with the companion wall.

4. A packing structure, including a non-metallic packing member adaptedto engage a companion wall, an.

abutment adjacent said member, a first split functionally integral ringengaging said packing member, a second split functionally integral ringengaging said abutment and said first ring and circumferentiallyslidable on said first ring, and means securing said rings to oneanother for joint movement toward engagement with the companion wall inresponse to movement of the packing member into engagement with thecompanion wall.

5. A packing structure, including a non-metallic packing member adaptedto engage a companion wall, an abutment adjacent said member, a firstsplit ring engaging said packing member, a second split ring engagingsaid abutment and said first ring and circumferentially slidable on saidfirst ring, one of said rings having an arcuate groove therein, and anarcuate rib on the other of said rings disposed in said groove to causeboth of said rings to move jointly toward engagement with the companionwall in response to movement of the packing member into engagement withthe companion Wall.

6. A packing structure, including a non-metallic packing member adaptedto engage a companion wall and having a first tapered expander surface,an abutment adjacent said member and having a second-tapered expandersurface opposite said first expander surface, a first split ringengaging said first tapered surface, a second split ring engaging saidsecond tapered surface and said first ring and circumferentiallyslidable on said first ring,

- 6 one ofsaid rings having an arcuate groove therein, the other of saidrings having an arcuate rib disposed said groove to cause said rings tomove jointly toward engagementwith the companion Wall in responsetomovement to the packing member into engagement with the companion "wall.

7. A packing structure, including a non-metallic packing member adaptedto engage a companion surrounding wall and having a first taperedexpander surface, an abutment adjacent said member andhaving a secondtapered expander surface opposite said first expander surface, a firstsplit ring engaging said first surface and having a generallycylindrical outer surface, a second splitring engaging said secondsurface and having a generally cylindrical outer surface, and meanssecuring said rings to one an; other for circumferentially shiftablerelation to each other and for joint outward expansion intoengagementwith the surrounding wall in response to movement of thepacking member toward said abutment and into engagement withthecompanion wall.

8. A packing structure, including a non-metallic packing member adaptedto engage a companion surrounding wall and having a first taperedexpander surface, an abutment adjacent said member and having a secondtapered expander surface opposite sai d first expander surface, a I

first split ringengaging said first surface and having a, generallycylindrical outer surface, a second split ring engagingsaid secondsurface and having a generally cylindrical outer surface andcircumferentially slidable on said first ring, one of said ringshavingan arcuate groove therein, and an arcuate rib on the other of said ringsdisposed in said groove to cause said rings to expand jointly intoengagement with the surrounding wall in response to movement of thepacking member toward said abutment and into engagement with thesurrounding wall.

9. A packing structure, including a non-metallic packing member adaptedto engage a companion surrounding wall and having a first taperedexpander surface, an abutment adjacent said member and having a secondtapered expander surface opposite said first expander surface, a firstsplit ring of generally triangular cross-section having a taperedsurface engaging said first surface and also having a generallycylindrical outer surface, a second split face and disposed in saidarcuate groove to cause said. rings to move jointly outwardly intoengagement with the surrounding wall in response to movement of thepacking member towards said abutment and into engagement with thesurrounding wall.

10. A packing structure, including a non-metallic packing member adaptedto engage a companion wall, an abutment adjacent said member and havinga tapered expander surface, a first split functionally integral ductilering engaging said packing member, a second split functionally integralductile ring engaging said tapered surface and said first ring andcircumferentially slidable on said first ring, and means securing saidrings to one another for joint movement toward engagement with thecompanion wall in response to movement of the packing member intoengagement with the companion wall.

ll. A packing structure, including a non-metallic packing member adaptedto engage a companion wall, an abutment adjacent said member, a firstsplit functionally integral ductile ring engaging said packing member, asecond split functionally integral ductile ring engaging said abutmentand said first ring and circumferentially slidav rings disposed in saidgroove to cause both of said rings to move jointly toward engagementwith the companion wall in response to. movement of the packing memberinto engagement with the companion Wall.

12. A packing structure, including a non-metallic packing member adaptedto engage a companion surrounding wall and having a first taperedexpander surface, an abutment adjacent said member and having a secondtapered expander surface opposite said first expander surface, a firstsplit functionally integral ductile ring engaging said first surface andhaving a generally cylindrical outer surface, a second splitfunctionally integral ductile ring engaging said second surface andhaving a generally cylindrical outer surface, and means securing saidrings to one another for circumferential shifting relative to each otherand for joint outward expansion into engagement with the surroundingwall in response to movement of the packing member toward said abutmentand into engagement with the companion wall.

13. A packing structure, including a non-metallic packing member adaptedto engage a companion wall, an abutment adjacent said member, a firstsplit functionally integral ductile ring engaging said packing member, asecond split functionally integral ductile ring engaging said abutmentand said first ring and circumferentially slidable on said first ring,and means securing said rings to one another for joint movement towardengagement with the companion wall in response to movement of thepacking member into engagement with the packing -wall.

14. A packing structure, including a non-metallic packing member adaptedto engage a companion surrounding wall and having a first taperedexpander surface, an abutment adjacent said member and having a secondtapered expander surface opposite said firstexpander surface, a firstsplit functionally integral ductile ring, a generally triangularcross-section having a tapered surface engaging said first surface andalso having agenerally cylindrical outer surface, a second splitfunctionally integral ductile ring and generally triangular crosssectionhaving a tapered surface engagingsaid second surface and also having agenerally cylindrical outer surface, said rings being circumferentiallyshiftable relative to each other and having opposed surfacessubstantially normal to said outer surfaces and engaging one another,one of said rings having an arcuate groove extending in an axialdirection inwardly from its normal surface, and the other of said ringshaving an arcuate rib projecting axially from its normal surface anddisposed in said arcuate groove to cause said rings to move jointlyoutwardly into engagement with the surrounding wall in response tomovement of the packing member toward said abutment and into engagementwith the surrounding wall.

References Cited in the file of this patent UNITED STATES PATENTS2,368,928 King Feb. 6, 1945 2,546,377 Turechek Mar. 27, 1951 2,695,068Baker et al Nov. 23, 1954 2,726,722 Baker Dec. 13, 1955

